n.

As soon as the food is reduced to a state of fluidity, the pyloric
orifice of the stomach is unclosed, and it is thrust onwards through
the alimentary canal, receiving in the duodenum the secretions of the
liver and pancreas, after which it yields to the lacteals its nutrient
portion, and the residuum is expelled from the body.

There have been many hypotheses in regard to the nature of the
digestive process. Some have supposed that digestion is a mere
mechanical process, produced by the motion of the walls of the
stomach; while others, in later times, have considered it as under the
influence of a spirit separate from the individual, who took up his
residence in the stomach and regulated the whole affair; while others
still would make it out to be a chemical operation, and thus
constitute the stomach a sort of laboratory. But to all these
ridiculous hypotheses Sir John Hunter has applied the following
playful language: "Some will have it that the stomach is a mill;
others that it is a fermenting vat; and others that it is a stewpan;
but in my view of the matter, it is neither a mill, a fermenting vat,
nor a stewpan, but a stomach, _a stomach_!"

At the present day this process is regarded as a complex, and not a
simple operation. It seems to be a process in which the mechanical,
chemical, and vital agencies must all act in harmony and order; for if
one of these be withdrawn, the function cannot be sustained for any
considerable length of time; and of the chemical and mechanical parts
of the process, since the former is much more important, and, as a
matter of course, the vital powers are indispensable, therefore
digestion may be considered as a chemical operation, directly
dependent on the laws of vitality, or of life; since the proper
consistency of the food depends, in a great measure, upon the
character of the solvents, while the secretion of these fluids, their
proper amount, together with the peculiar instinct--as it almost
seems to be--necessary to direct the stomach in its many functions,
are exclusively and entirely dependent on the laws and conditions of
life.

G.

As food is necessary to supply the waste and promote the growth of the
body, it follows that that will be the best adapted to the system
which contains the same chemical elements of which the body is
composed; viz., oxygen, hydrogen, carbon, and nitrogen. These elements
are found in greater or less quantity in all animal food, and in ma